3d scanner with steam autoclavable tip containing a heated optical element

ABSTRACT

A 3D scanner for recording topographic characteristics of a surface of at least part of a body orifice, where the 3D scanner includes a main body having a mounting portion; a tip which can be mounted onto and un-mounted from the mounting portion, where the tip is configured for being brought into proximity of the body orifice surface when recording the topographic characteristics such that at least one optical element of the tip is at least partly exposed to the environment in the body orifice during the recording; and a heater for heating the optical element, where the heat is provided by way of thermal conduction; where the tip can be sterilized in a steam autoclave when un-mounted from the main body of the 3D scanner such that it subsequently can be reused.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.14/553,588, filed on Nov. 25, 2014, which is a continuation of U.S.application Ser. No. 14/383,699, filed on Sep. 8, 2014, now U.S. Pat.No. 9,204,804, which is a U.S. national stage of InternationalApplication No. PCT/EP2013/054803, filed on Mar. 9, 2013, which claimsthe benefit of U.S. Provisional Application No. 61/617,782, filed onMar. 30, 2012, the benefit of U.S. Provisional Application No.61/608,831, filed on Mar. 9, 2012, and the benefit of Danish ApplicationNo. PA 2012 70162, filed on Mar. 30, 2012. The entire contents of eachof U.S. application Ser. No. 14/553,588, U.S. application Ser. No.14/383,699, U.S. Pat. No. 9,204,804, International Application No.PCT/EP2013/054803, U.S. Provisional Application No. 61/617,782, U.S.Provisional Application No. 61/608,831, and Danish Application No. PA2012 70162 are hereby incorporated herein by reference in theirentirety.

FIELD OF THE INVENTION

This invention generally relates to 3D scanners. More particularly, theinvention relates to 3D scanners for scanning surfaces in humidenvironments and/or in environments with high requirements to hygiene,such as in body orifices, where condensation on optical surfaces islikely to occur.

BACKGROUND OF THE INVENTION

In some embodiments, the invention relates to optical 3D scanning of thegeometry of body orifices, in particular in-ear scanning and intra-oralscanning. Scanners for this purpose are generally handheld. Inparticular the parts that enter the body orifice—generally some sort oftip, must fulfill requirements to hygiene and the quality of imagestaken. Optical signal quality deteriorates when condensation occurs onoptical elements such as lenses or filters. The afore-mentioned bodyorifices have a very humid, warm microclimate, so condensation willlikely occur on surfaces that, prior to insertion into the body orifice,were at ambient temperature.

The prior art has several approaches to prevent condensation on theoptical elements of intraoral, i.e., dental scanners.

U.S. Pat. No. 7,946,846 (Cadent Ltd) describes a tip with auxiliarynozzles that direct a stream of gas to or from the optical surfaces andthe teeth, in particular where the gas is at a temperature above bodytemperature. A flow of ambient air around exposed tissue can howeverincrease the risk of infections both for the patient and the dentist. Anair flow can also cause pain during dental treatment, and discomfort andnoise when scanning in the ear canal.

Other manufacturers of intraoral scanners use electrical elements toheat the optical elements exposed to the body orifice. These electricalelements can either be installed inside the scanner (e.g., 3M LavaC.O.S.), or externally, such that heating only occurs when the scanneris at rest outside the body orifice (e.g., Sirona Cerec has a heatingelement on a cart).

Manufacturers of intraoral scanners have used several approaches toproviding hygiene, particularly for those parts entering the bodycavity. Some manufacturers provide single-use tips (Cadent iTero). Forthe 3M Lava C.O.S. scanner, the manufacturer recommends single-useplastic sleeves, which however—because of a need for high imagequality—have a hole where the optical elements are located, and henceadditional surface sterilization by liquid agents is recommended. For atleast one device (Sirona Cerec), hot air sterilization is recommended bythe manufacturer. At least one scanner (3Shape TRIOS) has a removabletip that can be steam autoclaved.

Steam autoclaving is considered the safest general-purpose sterilizationmethod, and is accordingly recommended by authorities and standardized(e.g., EN 13060). Consequently, essentially all dental practices have aleast one steam autoclave, while hot-air autoclaves are uncommon. TheGerman Federal Institute for the Prevention of Infectious Diseases(Robert Koch Institut, RKI) has published a guideline for hygieneprocedures for dental devices based on the German implementation of theMedical Device Directive 93/42/EEC [1]. For instruments used inrestorative treatment (like a tip on an intraoral scanner), theguideline prescribes a sequence of cleaning in an instrument washer andsteam autoclaving. A similar guideline for the US has been published bythe Centers for Disease Control (CDC) [2].

While thus preferable from a hygiene perspective, the combination of aninstrument washer and a steam autoclave is harsh on materials andassembly agents such as glues. This is presumably is why apparently onlyone scanner on the market, 3Shape TRIOS, allows this optimal form ofsterilization.

SUMMARY

The invention disclosed herein solves both the condensation and thesterilization problems in the optimal way. This is performed byproviding a tip that both can be autoclaved and heated internally, i.e.,by the handheld scanner.

Disclosed is a 3D scanner for recording topographic characteristics of asurface of at least part of a body orifice, where the 3D scannercomprises:

-   -   a main body comprising a mounting portion;    -   a tip which can be mounted onto and un-mounted from said        mounting portion, where said tip is configured for being brought        into proximity of said body orifice surface when recording said        topographic characteristics such that at least one optical        element of the tip is at least partly exposed to the environment        in the body orifice during said recording; and    -   a heater system for heating said optical element, said heater        system comprising a source of electromagnetic energy and a        receptive element configured for receiving the electromagnetic        energy and converting it into heat, where the generated heat is        provided by way of thermal conduction directly to said optical        element or indirectly through a heat conducting element;    -   where the tip can be sterilized in a steam autoclave when        un-mounted from the main body of the 3D scanner such that it        subsequently can be reused.

It is an advantage over the prior art that heat can be transferred tooptical elements of the tip to prevent condensation, while the tip stillcan be autoclaved.

According to an aspect of the invention is disclosed a 3D scanner forrecording topographic characteristics of a surface of at least part of abody orifice, where the 3D scanner comprises:

-   -   a main body comprising a mounting portion;    -   a tip which can be mounted onto and un-mounted from said        mounting portion, where said tip is configured for being brought        into proximity of said body orifice surface when recording said        topographic characteristics such that at least one optical        element of the tip is at least partly exposed to the environment        in the body orifice during said recording; and    -   a heater system for heating said optical element, said heater        system comprising a source of electromagnetic energy and a        receptive element configured for receiving the electromagnetic        energy and converting it into heat, where the generated heat is        provided by way of thermal conduction directly to said optical        element or indirectly through a heat conducting element;    -   where said heating system and said tip are configured to provide        that the temperature of said optical element can be raised from        20 to 32 degrees C. within at most 60 minutes in 20 degrees C.        ambient temperature while the scanner is supplied with a rated        power input; and    -   where the tip can be sterilized in a steam autoclave when        un-mounted from the main body of the 3D scanner such that it        subsequently can be reused.

Disclosed is a 3D scanner for recording topographic characteristics of asurface of at least part of a body orifice, where the 3D scannercomprises:

-   -   a main body comprising a mounting portion;    -   a tip which can be mounted onto and un-mounted from said        mounting portion, where said tip is configured for being brought        into proximity of said body orifice surface when recording said        topographic characteristics such that at least one optical        element of the tip is at least partly exposed to the environment        in the body orifice during said recording;    -   where said tip comprises at least one optical element that is at        least partly exposed to the environment in the body orifice        during scanning and where the optical element is glued to a        sheet that is welded onto the body of the tip; and where the tip        can be sterilized in a steam autoclave when un-mounted from the        main body of the 3D scanner such that it subsequently can be        reused.

Disclosed is a tip for a 3D scanner for recording topographiccharacteristics of a surface of at least part of a body orifice, wherethe tip comprises:

-   -   a framework comprising a first opening configured for engaging a        mounting portion of a main body of a 3D scanner, and a second        opening configured for allowing light received from a surface to        enter the tip;    -   an optical element which at least partly is exposed to the        environment in the body orifice during said recording; and    -   means for providing heat to the optical element;    -   where the tip can be sterilized in a steam autoclave when        un-mounted from the mounting portion of the 3D scanner such that        it subsequently can be reused.

When scanning a body orifice of a patient using a 3D scanner, the partsengaging the body orifice must be sterile in order to avoid infectionsand the transfer of deceases from one patient to the next. For a 3Dscanner such as the one according to the present invention, the partengaging the body orifice is a tip which accordingly either must bereplaced by a new sterile tip or must be sterilized prior to scanning anew patient. It is an advantage of the present invention that the tip ofthe 3D scanner can be un-mounted from the mounting portion of the mainbody and that the tip can withstand being sterilized in an autoclave,since this allows the tip to be removed after scanning and to besterilized alone without the need for exposing the entire 3D scanner toa sterilization procedure. After sterilization the tip can mounted onthe scanner again and be reused for scanning the next patient.

In some embodiments, the tip is made capable of withstandingsterilization in an autoclave at least partly by the choice ofmaterials. The framework of the tip may be manufactured in a material,such as PSU, which is capable of withstanding autoclave. If a heatconducting element of the tip comprises a heat conductive layer whichcannot withstand the harsh treatment of an autoclave sterilizationprocess it may be protected by a protective layer of the heat conductingelement, such as a protective layer made in stainless steel.

In some embodiments, the tip is made capable of withstandingsterilization in an autoclave at least partly by heat stacking some ofthe components of the tip together, such as heat stacking the heatconductive element to the framework of the tip.

In some embodiments, the tip is made capable of withstandingsterilization in an autoclave at least partly by designing the tip suchthat all surfaces are easily accessible, e.g. by avoiding cavities inwhich biological material from the patient's body orifice can gather.This has the advantage that the problems for the autoclave procedure toaccess materials in such cavities are avoided.

In some embodiments, the source of electromagnetic energy is located inmain body.

Having the electromagnetic source located in the main body instead ofe.g. in the tip provides several advantages, such as in relation to theautoclaving of the tip since such sources rarely are designed to beautoclavable. Further, since the tip often is replaced after having beenused a number of times, e.g. 20 times, the cost of the tip should bekept low, and the units of the 3D scanner which can be used a largenumber of times should not be integrated in the tip.

Electromagnetic energy in the sense of this invention can be the energycontained in a DC, pulsating DC, or AC electric current or inelectromagnetic radiation or in a static or time-varying electromagneticfield.

In some embodiments, the mounting portion comprises a tube onto whichthe tip can be mounted onto and un-mounted from.

It is an advantage of this invention over U.S. Pat. No. 7,946,846 thatheating of the optical element occurs by way of thermal conduction, notconvection as in U.S. Pat. No. 7,946,846, as convection implies a riskof microbial contamination and pain for the patient.

In some embodiments, the optical element comprises a mirror, a lens, agrating, a filter, a prism, a window, and/or other optical parts. Theoptical element may at least partly be exposed to the environment in thebody orifice during said recording.

In the context of this invention, an optical element is any element thattransmits or reflects light that is employed in the 3D measurementfunction. The particular optical effect—if any—of the optical element isnot decisive in the sense of this invention, only the possibility ofcondensation occurring on at least part of its surface, thus affectingthe 3D measurement performance of the scanner.

Besides the at least one optical element in the tip, the 3D scanner mayhave at least one other optical element in the main body of the 3Dscanner on which condensation can potentially occur when the scanner isused for scanning in the body orifice. This can for example be a lens,prism or a window on a tube onto which the tip can be mounted. Also thetip may have additional optical elements not exposed to the environmentin the body orifice and not affected to condensation.

In the context of the present invention, the phrase “the remainder ofthe 3D scanner” is used in relation to the parts of the 3D scannerbesides the tip, i.e. the remainder of the 3D scanner may comprise themain body with the mounting portion of the 3D scanner.

In some embodiments, the scanner is configured to provide that theheater system provides heat to the optical element during at least apart of the recording. Heating the optical element during the recordinghas the advantage that the scanner can be used for a period of timewithout the risk of the temperature of the optical element decreasing toa level where condensation of moisture on the optical element ispossible.

The activation of the heating system may be controlled by a controlsystem of the scanner, such as a control system integrated in the mainbody. The control system may be configured for controlling both therecording of topographic characteristics and the heating of the opticalelement.

The body orifice can be a human mouth in which case the 3D scanner isconfigured for recording the surface of the teeth and/or the gingiva inthe patient's mouth. In this case the tip is preferable configured forbeing brought into the patient's mouth. The scanning can be based onfocus scanning such as the 3Shape Trios intra-oral scanner.

In some embodiments, at least part of the receptive element is arrangedat the mounting portion.

Having the receptive element being a part of the mounting portion hasthe advantage that the heat is produced at the mounting portion of the3D scanner i.e. relatively close to the tip where it can be conducted tothe optical element via e.g. a heat conducting element.

In some embodiments, the heating system comprises one or more elementsconfigured for transferring the electromagnetic energy from the sourceto the receptive element.

This may provide the advantage that the source of the electromagneticenergy and the receptive element can be arranged at some distancebetween each other such that the 3D scanner can be designed more freely.While the source of electromagnetic energy often is located in the mainbody, the receptive element configured for receiving the electromagneticenergy and converting it into heat can e.g. be located in the tip. Insuch cases, the elements configured for transferring the electromagneticenergy may be configured for transferring the electromagnetic energy tothe tip, e.g. by transferring the electromagnetic energy from a unit atthe mounting portion to a unit at the tip. The receptive element mayalso be arranged as a part of the mounting portion such that theelectromagnetic energy must be transferred to the mounting portion fromthe source.

In the context of the present invention when a feature of the tip isdescribed in relation to the mounting portion of the main body, it iscontemplated that the tip is mounted on the mounting portion.

In some embodiments, at least part of the receptive element is arrangedat the tip, and the elements configured for transferring theelectromagnetic energy are configured for transferring theelectromagnetic energy from the main body to the tip, such as from themounting portion to the tip.

Having the receptive element being a part of the tip has the advantagethat the heat may be generated immediately at or very close to theoptical element it is intended to heat such that the heating of theoptical element may occur with no or limited use of heat conductingelements and/or with limited dissipation of heat to other parts of thetip than the optical element.

In some embodiments, the elements configured for transferring theelectromagnetic energy comprises electrical conductive elements, such asconducting wires.

In some embodiments, the 3D scanner comprises a coil arranged at themounting portion and the tip comprises an element susceptible toinduction where the arrangement of the coil and the element susceptibleto induction is such that energy transfer to the tip can at least partlybe provided by induction. The element susceptible to induction cancoincide with the receptive element, such that the element susceptibleto induction is the element which converts the received electromagneticenergy into heat.

In some embodiments, the elements configured for transferring theelectromagnetic energy comprises a coil arranged at the mounting portionand an element susceptible to induction arranged at the tip, where thearrangement of the coil and the element susceptible to induction is suchthat an energy transfer from the coil to the element susceptible toinduction at least partly can be provided by induction when the tip ismounted on the mounting portion.

Transferring the electromagnetic energy by means of such an inductivecoupling provides the advantage that the 3D scanner is less sensitive tomanufacturing tolerances which may result in a situation with a poorphysical contact or even no contact between parts of the energytransferring elements arranged on the tip and parts arranged on themounting portion.

In some embodiments, the element susceptible to induction is configuredto be heated by the induction provided energy transfer and to providesaid heat directly to said optical element or indirectly by way ofthermal conduction through a heat conducting element.

In some embodiments, the source of electromagnetic energy comprises apower source and the receptive element of the heater system comprises anelectrical heater element, such as an electrical heater element arrangedat the mounting portion.

This has the advantage that the heat is produced at the mounting portionof the 3D scanner i.e. relatively close to the tip where it can beconducted to the optical element via e.g. a heat conducting element.

In some embodiments, the electrical heater element comprises a resistiveelement.

In some embodiments, a thermal connection is established between theelectrical heater element and the heat conducting element when the tipis arranged at the mounting portion, such that an energy transfer fromthe electrical heater element to the heat conducting element at leastpartly can be provided by thermal conduction.

In some embodiments, the receptive element coincides with the heatconducting element, such that a single element both receives theelectromagnetic energy, converts it into heat, and provides thegenerated heat to said optical element by way of thermal conduction.

In the context of this invention, two elements are said to coincide whena single physical element has the combined functions of the twoelements.

In inductive heating, heat is generated due to resistive losses relatedto eddy currents or due to magnetic hysteresis losses.

In some embodiments, the heat conducting element is arranged at the tipsuch that it can transfer heat generated by the receptive element tosaid optical element.

Using heat conducting element allows for a having a distance between thereceptive element and the optical element thus providing a large degreeof freedom in the design of the 3D scanner and its tip. Further in somecases, two or more optical elements must be heated. Having a heatconducting element distributing the generated heat may provide that onlyone receptive element is required.

In some embodiments, energy transfer is at least partly provided bytransmission of electrical power from a power source to a receptiveelement on the tip. This can be obtained by arranging an electricalheater element at the tube, such as at the side of the tube or insidethe tube.

In some embodiments, electrical power is transferred by means of themounting portion, such as a cable running alongside a tube onto whichthe tip is mounted.

In some embodiments, the source of electromagnetic energy comprises asource of electromagnetic radiation, such as a light source, and thereceptive element is configured for absorbing electromagnetic radiationand converting it into heat, i.e. energy transfer to the optical elementin the tip is at least partly provided by the electromagnetic radiation,such as visible radiation and/or infrared radiation.

The source of electromagnetic radiation is preferably contained in thescanner.

The receptive element configured for absorbing the electromagneticradiation, may be located in thermal contact with the optical element,such that heat transfer between the two elements may occur by thermalconduction. The receptive element can also coincide with the opticalelement. Energy transfer can be effective when the optical elementitself is absorptive in the range of wavelengths emitted by the source,thus transforming radiation to thermal energy.

The light source may be used for transferring electromagnetic energyonly or it may at least partly also used for the 3D measurementfunction. In some embodiments, one wavelength of the light source isused for heating while one or more other wavelengths are used for the 3Dmeasurement function.

In some embodiments, the scanner's light source is configured to emitelectromagnetic radiation at multiple wavelengths, such as at two ormore wavelengths, the absorbing receptive element is located behind theoptical element, and the optical element is transparent at one or moreof the wavelengths. The absorptive receptive element is preferablycapable of absorbing electromagnetic radiation with at least one of thewavelengths and converting the electromagnetic radiation into heat. Afurther elaboration of this example is an optical element that isreflective to wavelengths that are used in the 3D measurement function,but transmissive to those absorbed by the absorptive element.

In some embodiments, an absorptive receptive element can coincide withthe optical element. In such embodiments, the scanner's light source isconfigured to emit electromagnetic radiation at multiple wavelengths,such as at two or more wavelengths.

The absorptive receptive element is capable of absorbing electromagneticradiation with at least one of the wavelengths and converting theelectromagnetic radiation into heat. A further elaboration of thisexample is an optical element that is reflective to wavelengths that areused in the 3D measurement function, but absorbs other wavelengthsemitted by the scanner's light source.

In some embodiments, the absorptive element can be covered by someprotective material making autoclaving possible. Energy transfer byradiation may require fewer parts and hence allow a tip with a smallercross sectional area.

In some embodiments, the mounting portion and the tip are configuredsuch that the tip can be mounted in multiple positions, such as at leasttwo positions.

In some embodiments, the tip can also be washed in a medical instrumentwasher to clean the tip after use, i.e. the tip is configured towithstand being washed in a medical instrument washer, such that itsubsequently can be reused.

In some embodiments, the tip comprises a RFID unit, such that theheating function of the 3D scanner by which the tip is heated iscombined with an RFID function. The RFID unit may be configured toprovide that the tip can be identified, i.e. the RFID function may beused to identify tips. Different tips may be equipped with RFID tagsproviding signals that allow an individual identification of differenttips.

In some embodiments, the 3D scanner is configured to provide thatinformation provided by the RFID unit can be used to count the number oftimes each of a multitude of tips has been mounted on the scanner.

Inductive heating can be combined in function with RFID. For example, atag can be integrated into the tip and read via the receptive element.In this way, the number of times a particular tip has been mounted canbe counted, and stored either on some connected PC or written to the tagitself. This is advantageous if tips have a known and/or permittedmaximum number of uses.

In some embodiments, the tip of the handheld 3D scanner is removablesuch that it can be mounted on and unmounted from the remainder of the3D scanner, such as from the mounting portion and the main body of the3D scanner. At least part of the tip can come into physical contact withthe scanned body orifice. The contact may not be intentional, as opticalscanning generally is a non-contact technology, but inadvertent physicalcontact can generally not be excluded. The remainder of the scanner, incontrast, does typically not come into contact with the body orificewhen the scanner is used as intended. It is advantageous to separate thetip from the remainder of the scanner in this way, because the highhygienic requirements can be confined to the tip.

The tip can be steam-autoclaved at least at 122 degrees Celsius, andpreferably at 134 degrees Celsius. Preferably the tip can be autoclavedby a class B autoclave as defined in EN 13060. The remainder of thescanner can typically not be autoclaved, but possibly, it can bedisinfected and/or sterilized by other means. Preferably, the tip can beautoclaved multiple times.

The tip can be cleaned prior to steam autoclaving. One method ofproviding cleaning can be use of a medical/dental instrument washer.Such appliances typically reach temperatures over 90 degrees Celsius,considerably higher than household dish washers that they otherwiseresemble.

During scanning, condensation on the at least one optical element in thetip can be prevented or at least significantly reduced by heating saidoptical element. If another optical element is arranged on the remainderof the scanner on which condensation may occur, this optical element canalso be heated.

Conductive heating by transfer of waste heat as generated by otherelectrically powered components in the scanner, e.g., motors, dataprocessing electronics, light source, and/or other, cannot generallyalone heat the optical element in the tip to 35 degrees C., for variousreasons. For one, the scanner is a medical device and therefore subjectto the standard IEC 60601-1-1 in most legislations. Here, IEC 60601-1-1is referred to in its 3^(rd) edition. According to IEC 60601-1-1 clause13.1.2, a rated power input exceeding 15 W results in tight restrictionson the choice of materials, tighter requirements for protection againstsingle fault conditions, and other. Even when more than 15 W input powerwere available, waste heat would also heat other surfaces of thescanner, with a risk of temperatures there surpassing the limits set byIEC 60601-1-1 chapter 11. Furthermore, to achieve electrical insulationtowards the patient according to IEC 60601-1-1 chapter 8, the tip ispreferably made of some insulating material with correspondingly smallthermal conductivity. A tip made of metal, on the other hand, woulddissipate heat, again increasing the amount of waste heat that would benecessary. In general, the tight restrictions enforced by IEC 60601-1-1cannot be met trivially, indicating the significance of the inventiondescribed here. The rated power input is effectively restricted by atleast compliance with IEC 60601-1-1.

In some embodiments, the heating functionality is integrated in thehandheld scanner. In this manner, there is no need for any additionaldevice containing an external heating element, nor is there any need forany air flow along the optical element. It is preferable that at leastsome degree of heating can be provided during scanning. For condensationto be avoided in practice, the optical element has to be at atemperature of at least 32 degrees C., and preferably above normal humanbody temperature.

For the function of heating the at least one optical element, thescanner according to this invention comprises at least one receptiveelement designed to convert electromagnetic energy to be to heat whichis transferred at least indirectly to the optical element in the tip byway of thermal conduction.

In some embodiments, the receptive element is located outside the tip inthe main body of the 3D scanner, such as on the mounting portion, and isa resistive element that generates heat to be conducted to the opticalelement, directly or indirectly via a thermal conducting element.

Internal heating is advantageous as it prevents condensation withouttime limitation, whereas the effectiveness of external heating islimited in time by the thermal inertia of the optical elements in thescanner tip.

In some embodiments, the 3D scanner comprises an electrically poweredelement located outside the tip in the main body of the 3D scanner, andenergy is transferred to the tip by means of induction, and converted toheat by some receptive element in the tip.

In some embodiments, a combination of conductive and inductive heatingis implemented in a single element.

In some embodiments, an electrically powered resistive heating elementis located on the tip, with power supplied from the remainder of thehandheld 3D scanner, such as from the main body of the scanner. Thetransfer of electrical power can be by physical contact. Other ways totransfer electrical power is by means of induction, or by wireless powertransfer, or others.

Thermal conduction can be implemented by metallic and/or non-metallicelements. An example of the latter is graphite.

For those embodiments that employ inductive heating, the tip mustcontain a material, usually a kind of metal, that is receptive toinduction heating. Because the tip preferably also should be such thatis can be autoclaved, said material must also be robust to corrosion.Magnetic stainless steel fulfills both above criteria. Other metals withhigher thermal conductivity than stainless steel, e.g., copper andaluminum, can be suitable for this invention after anti-corrosivesurface treatment such as nickel or nickel-tin plating. Another solutionis to compose a heater element within the tip of two constituents, thefirst being receptive to induction, and the second having a higherthermal conductivity than the first. Such a second constituent can alsocontain at least one non-metallic material such as graphite.

In a 3D scanner according to the present invention, heating of theoptical element in the tip can be sufficiently quick for a typicalintended use of the scanner. A typical intended use can be in relationto a treatment, for example a dentist's appointment or an earexamination. The heating speed requirement can be tested as follows: Theentire scanner with tip is initially at 20 degrees Celsius, and this isalso ambient temperature. The heating is sufficiently quick if the atleast one optical element in the tip reaches 32 degrees C. within 60minutes, while the ambient temperature remains 20 degrees C., and thetotal power input to the scanner is in accordance with IEC 60601-1-1,and the scanner is held in some fixture that does not provide any othersource of heat and that does not touch the tip. Preferably, the 32degrees C. are attained in 10, more preferably in 2 minutes, and evenmore preferably in less than 1 minute. The requirement for quick heatingis another argument against the use of waste heat alone. Even if it didachieve 32 degrees at thermal equilibrium, it would take too much timeto be acceptable by the typical user.

In some embodiments, said heating system and said tip are configured toprovide that the temperature of said optical element can be raised from20 to 32 degrees C. within at most 60 minutes in 20 degrees C. ambienttemperature while the scanner is supplied with a rated power input, suchas where the temperature of said optical element can be raised from 20to 32 degrees C. within at most 30 minutes, such as within at most 15minutes, such as within at most 10 minutes, such as within at most 5minutes, such as within at most 2 minutes, such as within at most 1minute.

To prevent condensation, the optical element must be heated to above thedew point prevalent in the body orifice. Experience shows the dew pointis typically below 32 degrees C. In some embodiments of the invention,the temperature of said optical element can also be raised to abovehuman body temperature, which is the highest possible value of the dewpoint in a human body orifice.

It is advantageous to maintain at least some degree of heating functionduring scanning in the body orifice. For a scanner with limited totalpower, typically less power will be available for the heating functionduring scanning, because the electronics active during scanning, such asthe image sensor, consume power as well. When the scanner is notactively scanning, in particular before scanning, more power can bededicated to the heating function, and it is advantageous to do so.

Achieving and maintaining some desired temperature on the opticalelement of the tip may require regulation, possibly implemented in anIC, e.g. PLD, CPLD, FPGA, MCU, GPU or obtained by discrete components.

An electrically powered element designed to provide electromagneticenergy to be transferred to the at least one optical element in the tipcan by supplied by a dedicated, potentially isolated power supply, abattery, and/or the scanner's power supply, or other power supply.

The kinds of body origins commonly scanned with 3D scanners include themouth and the ear canal. A 3D topography of at least some teeth isrequired for the manufacture of restorations and/or for orthodontictreatment. A 3D topography of at least part of the ear canal, typicallyat least beyond the first bend, is required for the manufacture ofcustom-made hearing aids.

The handheld scanner can transfer data to an external PC, which againmay be connected to a display, on which some, possibly processed datafrom the scanning are shown. The PC, display, and power supply may bemounted in a cart, a possibly mobile container with possibly anadditional function of assuring or contributing to the electrical safetyof the entire system.

In some embodiments, the 3D scanner is configured for providing the heatto the optical element during the recording.

In some embodiments, the 3D scanner comprises an electrical heaterelement arranged at the mounting portion such that there is a thermalconnection between the electrical heater element and the tip, such thatthe energy transfer at least partly can be provided by thermalconduction.

In some embodiments, the tip is configured such that it can besterilized in a steam autoclave when un-mounted from the main body ofthe 3D scanner.

In some embodiments, the heater system comprises a source ofelectromagnetic energy and a receptive element configured for receivingthe electromagnetic energy and converting it to heat, and providing saidheat to the optical element, directly or indirectly via intermediateelements.

In some embodiments the heat conducting element comprises a multi-layersheet comprising one or more heat conducting layers and a protectivelayer arranged such that it faces the mounting portion and providesmechanical protection to the heat conductive layers, the heat conductivelayers having a relatively higher thermal conductivity than saidprotective layer.

The protective layer may provide structural stability to the heatconducting layers and hence to the heat conducting element. The layersare preferably arranged such that when the tip is arranged at themounting portion, the protective layer is located between the heatconductive layers and the mounting portion thereby shielding the heatconducting layers from abrasion when the tip is being mounted such asbeing slid onto the scanner, and/or from corrosion that otherwise wouldoccur during autoclaving or cleaning in a medical instrument washer. Theprotective layer can for example be made from a non-magnetic or onlyslightly magnetic material such as stainless steel. The layer providingthermal conductivity can for example be made of eGraf (GrafTechInternational Holdings Inc.), which additionally has the advantage ofproviding strongly anisotropic conductivity.

In some embodiments, the heat conducting layer is arranged in a recessdefined in the protective layer defined e.g. by controlled etching ofthe protective layer.

In some embodiments, the heat conducting element and/or the heatconductive layer has an anisotropic thermal conductivity, with a higherconductivity in the direction towards the optical element than along thenormal of the heat conducting layers.

This has the advantage that the heat primarily is transported towardsthe optical element and not towards the framework of the tip, such thatwhen there is an efficient transfer of heat from the heat conductiveelement to the optical element, the heat predominantly heats the opticalelement and not the tip framework with its outer surfaces which may comein contact with the patient during a scanning. A heating the frameworkand the outer surface could potentially cause the patient significantdiscomfort and pose a regulatory problem. Further, the energyconsumption and the heating time required for heating the opticalelement are reduced.

In some embodiments, the ratio between the thermal conductivity in thedirection towards the optical element and the thermal conductivity alongthe normal of the heat conducting layers is in the range of about 2 toabout 200, such as in the range of about 5 to about 150, such as in therange of about 10 to about 125, such as in the range of about 20 toabout 100, such as in the range of about 25 to about 50.

In some embodiments, the multi-layer heat conducting element has athickness which is at most 2 mm or better at most 1 mm, such as at most0.5 mm, such as at most 0.4 mm.

In some embodiments, the means for providing heat to the optical elementcomprises a receptive element configured for receiving electromagneticenergy from a source of electromagnetic energy and converting it intoheat.

An advantage of using a receptive element to generate the heat is thatit can be located e.g. at the optical element or at an appropriate partof the mounting portion, and that only an insignificant amount of heatis generated up to the position of the receptive element.

In some embodiments, the receptive element and the optical element arearranged such that the generated heat is provided directly to theoptical element by way of thermal conduction.

This has the advantage that the generated heat can be applied quickly tothe optical element with only a limited loss of heat.

In some embodiments, the tip comprises a heat conducting elementarranged for conducting the heat to said optical element.

Including such a heat conducting element has the advantage that the heatcan be generated at one location, e.g. at a portion of the tip facing asurface of the mounting portion of the 3D scanner, and transported tothe optical element, thus allowing for a more freely designing of thetip.

In some embodiments, the heat conducting element is arranged such that athermal connection can be made between the heat conducting element andan electrical heater element of the mounting portion of the main body tothe heat conducting element.

In some embodiments, the heat conducting element is mechanicallyconstrained inside the tip such that is cannot fall out of said secondopening. When the tip is mounted on the scanner, the heat conductingelement then cannot fall out of the tip.

In some embodiment, the heat conducting element is mechanicallyconstrained inside the tip such that is cannot fall out when mounted onthe scanner.

In some embodiments, the heat conducting element has a geometryascertaining that it cannot fall out of tip during use, when the tip ismounted on the scanner.

Having the heat conducting element mechanically constrained inside thetip has the advantage that in case the heat conducting elementaccidentally is released from the inner surface of the framework of thetip, the heat conducting element still cannot fall out of the tip andinto the mouth of a patient.

In some embodiments, the optical element is attached more firmly to theheat conducting element than the heat conducting element is attached tothe remaining parts of the tip.

The optical element may be mounted in such a way that the bonding to theconductive element is stronger than the bonding of the heat conductingconductive element to the tip framework, such that the optical elementand the heat conductive element only can come loose as a compound, andhence the optical element cannot fall out of the tip.

This has the advantage that if the tip, e.g., is dropped on the floor,it is more likely that the heat conducting element separates from theframework of the tip than the optical element separates from the heatconducting element. The optical element alone is hence not likely tofall out of the tip. If the heat conducting element further ismechanically constrained inside the tip, there is hence no risk of partswhich had become loose after the drop will fall out of the tip and intothe mount of a patient during a subsequent scanning.

It is particularly advantageous to keep optical elements free fromcondensation when recording color along with 3D topographiccharacteristics. The color balance in recorded images can be distortedby levels of condensation still too slight to significantly deterioratethe signal needed to compute 3D topographic characteristics. Even slightdistortions in color balance are highly noticeable for the human eye.

Disclosed is a 3D scanner for recording topographic characteristics of asurface of at least part of a body orifice, where the 3D scannercomprises:

-   -   a main body;    -   a mounting portion attached to the main body;    -   a tip configured for being brought into close proximity of said        body orifice surface when recording said topographic        characteristics, where said tip can be sterilized in a steam        autoclave and be mounted onto and un-mounted from the mounting        portion of the 3D scanner; and    -   an electrically powered element configured for providing an        energy transfer to said tip, such that at least part of said tip        is heated by said energy transfer, where the heating by energy        transfer can raise the temperature of said optical element from        25 to 35 degrees C. within at most 10 minutes in 25 degrees C.        ambient temperature while the scanner is supplied with a rated        power input.

Disclosed is a 3D scanner for recording topographic characteristics of asurface of at least part of a body orifice, where the 3D scannercomprises:

-   -   a main body;    -   a mounting portion attached to the main body;    -   a tip configured for being brought into close proximity of said        body orifice surface when recording said topographic        characteristics, where said tip can be sterilized in a steam        autoclave and be mounted onto and un-mounted from the mounting        portion of the 3D scanner; and    -   where said tip comprises at least one optical element that is at        least partly exposed to the environment in the body orifice        during scanning and where the optical element is glued to a        sheet that is welded onto the body of the tip.

Disclosed is a scanner for recording the topographic characteristics ofthe surface of at least part of a body orifice, with a tip that duringsaid recording may come into physical contact with at least part of saidbody orifice, where said tip:

-   -   can be mounted and unmounted from the remainder of the scanner        without the use of any tool    -   when unmounted, can be sterilized in a steam autoclave    -   has at least one optical element that is at least partly exposed        to the environment in the body orifice    -   and    -   where the optical element is glued to a sheet that is welded        onto the body of the tip.

Disclosed is a 3D scanner for recording the topographic characteristicsof the surface of at least part of a body orifice, with a tip thatduring said recording may come into physical contact with at least partof said body orifice, where said tip:

-   -   can be mounted and un-mounted from the remainder of the scanner        without the use of any tool    -   when un-mounted, can be sterilized in a steam autoclave    -   has at least one optical element that is at least partly exposed        to the environment in the body orifice    -   and    -   where said tip is heated by energy transfer from an electrically        powered element other than a gas pump,    -   and    -   where said heating by energy transfer can raise the temperature        of said optical element from 20 to 32 degrees C. within at most        60 minutes in 20 degrees C. ambient temperature while the        scanner is supplied with its rated power input.

Disclosed is a 3D scanner for recording topographic characteristics of asurface of at least part of a body orifice, where the 3D scannercomprises:

-   -   a main body;    -   a mounting portion attached to the main body;    -   a tip configured for being brought into close proximity of said        body orifice surface when recording said topographic        characteristics, where said tip can be sterilized in a steam        autoclave and be mounted onto and un-mounted from the mounting        portion of the 3D scanner; and    -   an electrically powered element configured for providing an        energy transfer to said tip, such that at least part of said tip        is heated by said energy transfer, where the heating by energy        transfer can raise the temperature of said optical element from        25 to 35 degrees C. within at most 10 minutes in 25 degrees C.        ambient temperature while the scanner is supplied with a rated        power input.

Obtaining a three dimensional representation of the surface of an objectby scanning the object in a 3D scanner can be denoted 3D modeling, whichis the process of developing a mathematical representation of thethree-dimensional surface of the object via specialized software. Theproduct is called a 3D model. A 3D model represents the 3D object usinga collection of points in 3D space, connected by various geometricentities such as triangles, lines, curved surfaces, etc. The purpose ofa 3D scanner is usually to create a point cloud of geometric samples onthe surface of the object.

3D scanners collect distance information about surfaces within its fieldof view. The “picture” produced by a 3D scanner describes the distanceto a surface at each point in the picture.

For most situations, a single a scan or sub-scan will not produce acomplete model of the object. Multiple sub-scans, such as 5, 10, 12, 15,20, 30, 40, 50, 60, 70, 80, 90 or in some cases even hundreds, from manydifferent directions may be required to obtain information about allsides of the object. These sub-scans are brought in a common referencesystem, a process that may be called alignment or registration, and thenmerged to create a complete model.

Iterative Closest Point (ICP) is an algorithm employed to minimize thedifference between two clouds of points. ICP can be used to reconstruct2D or 3D surfaces from different scans or sub-scans. The algorithm isconceptually simple and is commonly used in real-time. It iterativelyrevises the transformation, i.e. translation and rotation, needed tominimize the distance between the points of two raw scans or sub-scans.The inputs are: points from two raw scans or sub-scans, initialestimation of the transformation, criteria for stopping the iteration.The output is: refined transformation. The algorithm steps can be:

-   -   1. Associate points by the nearest neighbor criteria.    -   2. Estimate transformation parameters using a mean square cost        function.    -   3. Transform the points using the estimated parameters.    -   4. Iterate, i.e. re-associate the points and so on.

An intra-oral or in-ear scanner may be configured for utilizing focusscanning, where the digital 3D representation of the scanned teeth isreconstructed from in-focus images acquired at different focus depths.The focus scanning technique can be performed by generating a probelight and transmitting this probe light towards the set of teeth suchthat at least a part of the set of teeth is illuminated. Light returningfrom the set of teeth is transmitted towards a camera and imaged onto animage sensor in the camera by means of an optical system, where theimage sensor/camera comprises an array of sensor elements. The positionof the focus plane on/relative to the set of teeth is varied by means offocusing optics while images are obtained from/by means of said array ofsensor elements. Based on the images, the in-focus position(s) of eachof a plurality of the sensor elements or each of a plurality of groupsof the sensor elements may be determined for a sequence of focus planepositions.

The in-focus position can e.g. be calculated by determining the lightoscillation amplitude for each of a plurality of the sensor elements oreach of a plurality of groups of the sensor elements for a range offocus planes. From the in-focus positions, the digital 3D representationof the set of teeth can be derived.

3D modeling is the process of developing a mathematical, wireframerepresentation of any three-dimensional object, called a 3D model, viaspecialized software. Models may be created automatically, e.g. 3Dmodels may be created using multiple approaches: use of NURBS curves togenerate accurate and smooth surface patches, polygonal mesh modelingwhich is a manipulation of faceted geometry, or polygonal meshsubdivision which is advanced tessellation of polygons, resulting insmooth surfaces similar to NURBS models.

The present invention relates to different aspects including the devicedescribed above and in the following, and corresponding devices, eachyielding one or more of the benefits and advantages described inconnection with the first mentioned aspect, and each having one or moreembodiments corresponding to the embodiments described in connectionwith the first mentioned aspect and/or disclosed in the appended claims.

The use of the invention is not limited to 3D scanners but can also beapplied to 2D cameras, such as intraoral 2D cameras for acquiring a 2Dimage of a patient's teeth. This can e.g. be used in relation to cariesdetection where light from the 2D camera excite fluorescent materials inteeth and the 2D camera detect emitted fluorescence.

Disclosed is hence a 2D camera for recording topographic characteristicsof a surface of at least part of a body orifice, where the 2D cameracomprises:

-   -   a main body comprising a mounting portion;    -   a tip which can be mounted onto and un-mounted from said        mounting portion, where said tip is configured for being brought        into proximity of said body orifice surface when recording said        topographic characteristics such that at least one optical        element of the tip is at least partly exposed to the environment        in the body orifice during said recording; and    -   a heater system for heating said optical element, said heater        system comprising a source of electromagnetic energy and a        receptive element configured for receiving the electromagnetic        energy and converting it into heat, where the generated heat is        provided by way of thermal conduction directly to said optical        element or indirectly through a heat conducting element;    -   where the tip can be sterilized in a steam autoclave when        un-mounted from the main body of the 2D camera such that it        subsequently can be reused.

Disclosed is a tip for a 2D camera for recording images of a surface ofat least part of a body orifice, where the tip comprises:

-   -   a framework comprising a first opening configured for engaging a        mounting portion of a main body of a 2D camera, and a second        opening configured for allowing light received from a surface to        enter the tip;    -   an optical element which at least partly is exposed to the        environment in the body orifice during said recording; and    -   means for providing heat to the optical element;    -   where the tip can be sterilized in a steam autoclave when        un-mounted from the mounting portion of the 2D camera such that        it subsequently can be reused.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and/or additional objects, features and advantages of thepresent invention, will be further elucidated by the followingillustrative and non-limiting detailed description of embodiments of thepresent invention, with reference to the appended drawings, wherein:

FIGS. 1 and 2 show how a tip can be arranged at the tube of a handheldscanner.

FIG. 3 shows a cross section of a tip.

FIG. 4 shows a schematic drawing of a tube and some electronics.

FIGS. 5a and 5b show an example of a scanner tip according to thepresent invention.

FIGS. 6a and 6b show a tip comprising a multi-layer heat conductingelement.

FIG. 7 shows a 3D drawing of an example of a sheet.

FIG. 8 shows an example of an embodiment in which energy transfer is byelectromagnetic radiation.

FIG. 9 shows a welding solution for the tip.

FIG. 10 shows an embodiment with an electrically powered, resistiveheater element.

FIG. 11 shows an embodiment using wireless transmission of electricalenergy.

FIG. 12 shows schematic representation of the 3D scanner.

DETAILED DESCRIPTION

In the following, a few embodiments of the invention are described indetail. While the description also includes alternatives to some aspectsof the embodiments, the described embodiments are only examples of manypossible embodiments within the scope of this invention, and hence theinvention is not limited to the following description.

In the following description, reference is made to the accompanyingfigures, which show by way of illustration how the invention may bepracticed.

In the following, the reference numbers formatted as 1XX refers tofeatures of the tip, and reference numbers formatted as 2XX refers tofeatures of the main body of the scanner.

In FIG. 1, the scanner is an intraoral scanner that records the 3Dtopography of the teeth and parts of the surrounding issue. The user(typically the dentist) mounts the tip 100 on the mounting portion 201which here is a tube that is a fixed part of the main body 200 of thehandheld scanner. In the sense of the above general description, thetube is part of the main body of the scanner. The tube can have any formof cross section. A part of the optical path is inside the tube 201,substantially along the tube's axis.

At the end of a treatment, the user (dentist) unmounts the tip 100,which is then sterilized by at least autoclaving. Subsequently, the tipcan be reused for treatment of another patient, essentially without anyrisk of cross contamination. The mounting and un-mounting operations areeasy to perform for the user and require no tools. The tip 100 cansimply be slid onto the tube 201, where it snaps onto balls 202, onepressed into each of two opposing sides of the tube (FIG. 1 shows onlyone side of the tube and thus only one ball). Other means fortemporarily fixating the tip to the mounting portion of the 3D scannercan evidently be used instead of the balls.

Autoclavable in the sense of this invention means that the tip can betreated in a steam autoclave in the same manner as other dentalinstruments, e.g., a dental mirror, and subsequently used for scanningat least once.

Other parts of the main body of the 3D scanner are additional opticalelements, an image sensor, processing electronics, a control unitconfigured for controlling the heating system and/or the topographyrecording, an outer shell, amongst others. All these other parts are notcentral to this invention and thus not shown specifically in FIG. 1. The3D scanner can also comprise a light source. A light source is a centralpart in some embodiments of this invention.

In the design illustrated in FIGS. 1 and 2, but not necessarily ingeneral, the tip can be mounted in two positions on the tube 201. InFIG. 2, the tip 100 is in the opposite position relative to the tube 201compared to the position illustrated in FIG. 1. Given that the tip alsocontains a mirror for directing the light path to and from the teeth,the scanner can thus be used for recording the upper or lower teeth,respectively, in a convenient manner. In this embodiment, the opticalelement in the tip is thus the mirror.

FIG. 3 shows a cross section of the tip 100 containing the opticalelement, here a mirror 103, which is exposed to the environment in thebody orifice during said recording. The framework 104 of the tip can bemade of plastic by injection molding. Several plastic materials existsuitable for parts to be autoclaved, for example PSU. With appropriateglue, the mirror can be glued to the plastic. Because of the smallnumber of glues that both can be autoclaved and adhere to autoclavableplastic, another method of fixing the mirror is to weld a thin sheet 105made of some other material, e.g., metal to the plastic material and useglue to bond the mirror to that sheet. There is a much wider choice ofautoclavable glues that bond metal to glass. The bonding requirementsare high because commonly, a risk analysis will show that the tip mustpass a drop test. A welding solution is described in detail below.

FIG. 4 shows an example of an embodiment in which the tube 201 has atransparent front window 203. Because the tip is not closed (notice theopening at the mirror 103 in FIG. 3), the outward-facing surface of thiswindow 203 is also exposed to the environment in the body orifice e.g.to the patient's breath, and without preventive measures, there wouldalso be a risk of condensation occurring on this surface

Condensation on the front window 203 in the tube 201 is prevented byheating the tube and thus the window 203 and the mirror 103 via thermalconduction. An electrical heater element 204 is placed on a side of thetube. The electrical heater element is electrically isolated from thetube 201, as to prevent any risk of electric shock to the patient and/orthe operator. The heater element is resistive, and electric power to itis supplied by the source of electromagnetic energy which here is partof the scanner's electronics (partly shown as 205), which also areelectrically isolated from the tube. The scanner is supplied withelectrical power from mains and/or a battery. Note that the heaterelectrical element 204 in practice is covered by a thin sheet ofelectrically insulating material; as it would hide the heater element isit however not shown in FIG. 4.

FIG. 4 also shows a plastic ring 206 that provides electrical insulationbetween the tube 201 and the main body of the 3D scanner, for electricalsafety reasons. The plastic material also limits the conduction of wasteheat from the main body of the 3D scanner to the tip, indicating theimportance of the invention since heating of the tip would be veryinefficient if the heater was arranged in the main body of the 3Dscanner. One ball 202 onto which the tip can snap is also illustrated inthe figure.

In FIG. 5a , the heat conducting element comprises a sheet 106 arrangedin the scanner tip. The sheet 106 is at least partly made of a heatconducting material and runs along the inside of the tip, extending frombehind the mirror 103 to the region that is designed to come intophysical contact with the tube (therefore the two arrows in the figurepointing at these two major sections of the sheet 106). When the tip ismounted on the tube and the tube is heated by providing electromagneticenergy to the electrical heater element 204, the generated heat istransferred by thermal conduction to the tip and all the way to themirror 103 via the heat conducting sheet 106. Note that the sheet 106can also be welded to the tip material in the same manner as the smallersheet 105. When the tube is heated the temperature of the mirror 103 andof the window 203 increases and condensation of moisture on the windowis prevented.

Even though the sheet 106 is designed to come into physical contact withthe tube 201, manufacturing tolerances may result in a situation wherethis contact is poor, or where there even is a small gap between thesheet and the tube. To provide a design that fulfills the purpose and isrobust to manufacturing tolerances, providing the electromagnetic energyto the receptive element and/or converting the electromagnetic energy toheat can also be through induction. This is implemented by theelectrical heater element 204 having its wiring arranged as a coil andsupplied with a time variant current, such that the electrical heaterelement also can function as an element configured for transferring theelectromagnetic energy. The wiring in the electrical heater element maybe implemented as tracks on a printed circuit board (PCB). In the designshown in this figure, the sheet 106 then functions both as the receptiveelement converting the electromagnetic energy into heat and as the heatconducting element though which the heat is provided to the opticalelement. The receptive element hence coincides with the heat conductingelement. Note that the coil is seen from the side in FIG. 5a , andbecause of its small height, it cannot be properly visualized in thefigure.

In some embodiments, the sheet 106 is made of magnetic stainless steel.A two-layer solution with a wear-resistant, induction-perceptive metalfacing the tube 201 and graphite on the side facing the framework 104 ofthe tip could be a suitable alternative.

The sheet 106 must not come off when mounted on/off the tube evenmultiple times. Likewise, the mounting operation must not create forcesby which the mirror in the tip can become detached. One solution forthese problems is to partly mold the sheet into the tip. Because the tipis entered into the patient's mouth, its height should be small.Therefore, the sheet is preferably thin, such as with a thickness ofless than 2 mm, such as with a thickness of less than 1 mm, such as witha thickness of less than 0.5 mm, such as with a thickness of less than0.3 mm.

A possibility of mounting the tip in two positions (facing up/down asshown in FIGS. 1 and 2) requires that heating be possible in bothpositions. To obtain an effective transfer of energy by induction underboth positions, multiple electrical heater elements 204 with coils canbe provided, for example at opposing sides of the tip (FIG. 5b ), witheither one designed to be in contact with a straight sheet, a strip,that runs along one side of the inside of the tip. The tip itself canremain unchanged relative to FIG. 5 a.

Another possibility similar to the one of FIG. 5a is shown in FIG. 6a .Here, the sheet 106 making up part of the heat conductive element iscomprised of two layers, a heat conducting layer 156 made of eGraf and aprotective layer 155 made of stainless steel. A recess has defined inthe protective layer by controlled etching and the heat conducting layeris arranged in said recess. The arrangement of the heat conductive layerand the protective layer is such that the protective layer shields theheat conducting layer from abrasion on the mounting portion of the mainbody when the tip is mounted on the 3D scanner. This stainless steelneed not be magnetic.

The stainless steel protective layer protects the eGraf layer when bothare mounted inside the tip 100. This is advantageous because eGraf alonewould get damaged in a medical instrument washer. On the other hand,stainless steel alone would only provide inferior thermal conductance,with a thermal conductivity about 25 times small than eGrafs.

Another advantage of eGraf is its anisotropy in thermal conductivity,which can be exploited to achieve a high heat transfer towards theoptical element, while keeping undesired heat transfer towards the tipand thus its outer surface, which may have patient contact, small. Inone realized configuration, the thickness of the heat conducting layeris 0.4 mm.

Details of the mounting of the eGraf-steel heat conductive element areshown in FIG. 6b , which shows that the insertion of the conductiveelement can be guided mechanically by “rails” 159 inside the tip (100).In the example, attachment of the sheet to the tip is by heat stacking,on area 158. A mirror (not shown) can be glued to the face 160 of thestainless steel layer. Neither the multi-layer sheet making up the heatconductive element nor the compound of sheet and mirror can fall outthrough the opening 161 of the tip, both due to the constraint providedby the “rails” 159, and due to a conical shape of the sheet, with theend holding the mirror being the narrower one (c.f., FIG. 6a ) and thebroader part of the sheet being large than the opening 161. The tipshown in FIGS. 6a and 6b can be mounted on a tube with one or multipleheater elements (c.f., FIGS. 5a and 5b ).

Another solution that achieves effective inductive heating in bothpositions is to leave the tube unchanged relative to FIG. 5a , but toprovide a more complex sheet that is folded to cover multiple sides ofthe inside of the tip, with different sections designed to come intocontact with only one heater element. FIG. 7 is a 3D drawing of anexample of such a sheet 106. The more complex sheet could be created byfolding, bending, and/or welding the edges. The mirror (not shown inFIG. 7) would be attached to the back side (not visible here) of theflap A in FIG. 7. To improve heat conduction, the flap A can beconnected to face B, but this is not shown because it would render FIG.7 difficult to understand. Likewise, face C can be connected to flap A.

FIG. 8 shows an example of an embodiment in which energy transfer is byelectromagnetic radiation. Here, the light source 207 in the scanner isa dual-color LED, and the mirror 108 is a dichroic mirror. In such anembodiment, the light source is the source of electromagnetic energy andis located in the main body of the scanner. The mirror reflects one ofthe two wavelengths of light generated by the LED, but lets the otherpass. The portion of light that is transmitted through the dichroicmirror is then absorbed by a receptive element 107, which can be thesame as the sheet 105 illustrated in FIG. 3. As the receptive element107 absorbs the light, it heats up, and hence it directly heats thedichroic mirror 108 that it is in physical contact with. For practicalpurposes, there is a thin layer of glue in between 107 and 108, bondingthese two elements to each other. The wavelength of the transmittedportion may be longer or shorter than the wavelength of the portiondirected towards the teeth by the dichroic mirror. In some embodiments,at least one wavelength is not visible, such as UV or IR light.

FIG. 9 shows a welding solution for the tip 100. Part (a) of the figureshows a cross section of the front part of the tip, from the sameperspective as FIG. 3. The design is for injection molding and has threestuds 110. Part (b) of the figure shows a matching thin metal sheet 105shown for clarity from the top, from a perspective orthogonal to that ofpart (a). The sheet has three holes 111. The sheet is assembled suchthat the studs 110 penetrate through the holes 111. Then, a hot tool ispressed onto the tips of the studs such that they melt, flatten, andthus hold the metal sheet in place. Finally, a mirror 103, 108 can beglued to the metal sheet (not shown in FIG. 9). The sheet 105 could alsobe made of a non-metallic material. Several autoclavable glues areavailable that can bond an autoclavable metal to glass or to othermetal, i.e., the substrates of which mirrors are typically made. Forsuch materials autoclavable metal can be advantageous.

FIG. 10 shows an embodiment of the tip with a receptive element 120located behind the mirror 103 and touching that mirror. The receptiveelement 120 comprises a resistive material and is electrically poweredi.e. the electromagnetic energy is converted by passing an electricalcurrent through the resistive material. Elements configured fortransferring the electromagnetic energy to the receptive element arearranged in the tube and in the tip. In the tip these elements include atwo-conductor cable 121 with a contact surface 122. In the tube 201these elements contain another contact surface 222, connected with atwo-conductor cable 221 to the source of electromagnetic energy (a powersource not shown in FIG. 10) located in the main body of the scanner orelsewhere. When the tip is slid onto the tube, physical and electricalcontact is established between the two contact surfaces 122 and 222,allowing electromagnetic energy to be transmitted to the receptiveelement 120 which thus can convert the electromagnetic energy to heatwhich is directly provided to the mirror 103 by thermal conduction. Notethat to provide the electrical circuit, the contact surface 122 isseparated into two zones by some electrical insulation 130, and in amatching configuration, the contact surface 222 is separated into twozones by some electrical insulation 230, with each conductor in thecable 121 and 221, respectively, connected to one zone. Alternatively122 and 222 are divided in two areas and mounted on two opposite sidesof the tip.

FIG. 11 shows an embodiment which is a modification of the one in FIG.10, now with the elements configured for transferring theelectromagnetic energy to the receptive element being based on wirelesstransmission of electromagnetic energy. The elements 142 and 242 includecoils, with power-transmitting element 242 being connected to the sourceof electromagnetic energy (a power source not shown in FIG. 11) locatedin the main body of the scanner or elsewhere. Electromagnetic energy canthus be transmitted in a wireless manner to the power-receiving element142 which is electrically connected to a receptive element, which hereis a resistive electrical heater element 120, by a two-conductor cable121, such that the mirror 103 can be heated by way of thermalconduction. For wireless power transfer to be efficient, the coils onelements 142 and 242 should be designed to be aligned when the tip ismounted on the tube. All other elements in FIG. 11 are to be understoodas in FIG. 10. Wireless transfer of electromagnetic energy can beadvantageous because corrosion of the contact surfaces 122 and 222 afterrepeated autoclaving may lead to poor electrical contact in theembodiment of FIG. 10.

FIG. 12 shows schematic representation of the 3D scanner. The source ofelectromagnetic energy 250 is arranged in the main body of the scanneror in another element which the main body is connected to, for examplean external power source. From there it provides electromagnetic energyto the receptive element 110 through one or more elements 251 configuredfor transferring the electromagnetic energy. The receptive element 110is configured for receiving the electromagnetic energy and converting itinto heat. The generated heat is provided by way of thermal conductiondirectly to the optical element 103 in the tip of the 3D scanner orindirectly through a heat conducting element.

Although some embodiments have been described and shown in detail, theinvention is not restricted to them, but may also be embodied in otherways within the scope of the subject matter defined in the followingclaims. In particular, it is to be understood that other embodiments maybe utilized and structural and functional modifications may be madewithout departing from the scope of the present invention.

In device claims enumerating several means, several of these means canbe embodied by one and the same item of hardware. The mere fact thatcertain measures are recited in mutually different dependent claims ordescribed in different embodiments does not indicate that a combinationof these measures cannot be used to advantage.

A claim may refer to any of the preceding claims, and “any” isunderstood to mean “any one or more” of the preceding claims.

It should be emphasized that the term “comprises/comprising” when usedin this specification is taken to specify the presence of statedfeatures, integers, steps or components but does not preclude thepresence or addition of one or more other features, integers, steps,components or groups thereof.

REFERENCES

-   [1] Infektionsprävention in der Zahnheilkunde—Anforderungen an die    Hygiene. Mitteilung der Kommission für Krankenhaushygiene and    Infektionsprävention beim Robert Koch-Institut.    Bundesgesundheitsblatt—Gesundheitsforschung—Gesundheitsschutz 2006:4-   [2] Centers for Disease Control and Prevention. Guidelines for    Infection Control in Dental Health-Care Settings—2003. MMWR 2003; 52    (No. RR-17).

1. A 3D scanner for recording topographic characteristics of a surfaceof at least part of a body orifice of a patient, where the 3D scannercomprises: a main body comprising a mounting portion; a tip configuredto be mounted onto and un-mounted from said mounting portion, where saidtip is configured for being brought into proximity of said body orificesurface when recording said topographic characteristics such that atleast one optical element of the tip is at least partly exposed to theenvironment in the body orifice during said recording; a heater systemfor heating said optical element, said heater system comprising a sourceof electromagnetic energy and a receptive element configured forreceiving the electromagnetic energy and converting the electromagneticenergy into heat, where the generated heat is provided by way of thermalconduction directly to said optical element or indirectly through a heatconducting element; and a control system configured to control heatingof the optical element; where the tip is configured to be sterilizedwhen un-mounted from the main body of the 3D scanner such that the tipsubsequently can be reused.
 2. A 3D scanner for recording topographiccharacteristics of a surface of at least part of a body orifice of apatient, where the 3D scanner comprises: a main body comprising amounting portion; a tip configured to be mounted onto and un-mountedfrom said mounting portion, where said tip is configured for beingbrought into proximity of said body orifice surface when recording saidtopographic characteristics such that at least one optical element ofthe tip is at least partly exposed to the environment in the bodyorifice during said recording; where said tip comprises at least oneoptical element that is at least partly exposed to the environment inthe body orifice during scanning and where the optical element is gluedto a sheet that is welded onto the body of the tip; and where the tip isconfigured to be sterilized when un-mounted from the main body of the 3Dscanner such that the tip subsequently can be reused.
 3. A tip for a 3Dscanner for recording topographic characteristics of a surface of atleast part of a body orifice of a patient, where the tip comprises: aframework comprising a first opening configured for engaging a mountingportion of a main body of a 3D scanner, and a second opening configuredfor allowing light received from a surface to enter the tip; an opticalelement which at least partly is exposed to the environment in the bodyorifice during said recording; and means for providing heat to theoptical element; where the tip is configured be sterilized whenun-mounted from the mounting portion of the 3D scanner such that the tipsubsequently can be reused.